Alpha Centauri is the nearest stellar system to Earth, at just over four light-years. It is a triple system:
- alpha-centauri-a — a Sun-like G-type star, the closest solar analog to our Sun
- Alpha Centauri B — a K-type star
- Proxima Centauri — a red dwarf, marginally closer than A/B, and host to three known planets (including habitable-zone Proxima b)
The A-B pair has an 11-35 AU separation, which constrains where stable planets can orbit either star. The system has long been a priority target for exoplanet searches and for proposed dedicated imaging missions like project-blue.
Notable 2026 development
jwst MIRI coronagraph observations reveal a candidate Saturn-like gas giant orbiting alpha-centauri-a at ~2 AU (src-alpha-centauri-a-exoplanet-2026). If confirmed, this would be the closest exoplanet ever detected in a Sun-like star’s habitable zone.